Hydraulic pumping system



Feb. 3, 1970 L. BEVANDICH HYDRAULIC PUMPING SYSTEM Filed Jan. 24, 1968I2 22 G3 PRIOR ART FIG.4

. INVENTOR LOU-IS BEVANDLCH FIG. 3

BUCKHORN, BLORE, K'LARQUIST & SPARKMAN ATTORNEYS United States Patent3,493,001 HYDRAULIC PUMPING SYSTEM Louis Bevandich, 4155 Philomath Road,Corvallis, Oreg. 97330 Filed Jan. 24, 1968, Ser. No. 700,048 Int. Cl.E031) 11/16; F161 55/04; B67d 5/54 U.S. Cl. 13714 12 Claims ABSTRACT OFTHE DISCLOSURE A hydraulic pumping system incorporating a constant speedmotor driving a pump to deliver water through a delivery pipe to one ormore outlets provided with shutoff valves. A hydraulic pressure storagedevice connected in parallel with the outlets provides for delivery offluid at a substantially constant pressure through the use of a motorshutoif switch sensitive to tank pressure so as to activate the motorwhen tank pressure drops below a predetermined minimum and so as todeactivate the motor when tank pressure rises to a predeterminedmaximum. A check valve interposed between the tank and main deliverypipe opens in a direction to permit rapid discharge of fluid from thetank when an outlet valve is opened, and a bypass orifice bypassing thecheck valve permits slow filling of the tank when the pump is operating.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates to hydraulic pumping systems and more particularly to a demandpressure system utilizing a motor-driven pump and a pressure-sensitiveswitch to operate the pump only on pressure demand.

Description of the prior art Referring to FIG. 1 of the drawing, theconventional prior art household water pumping system includes aconstant displacement pump driven by a constant speed motor 12 so as todeliver water through a pipe 14 to several outlets 16 having shutoffvalves 18. Downstream from the pump a hydraulic pressure accumulator inthe form of a conventional pressure tank (not shown) or an expansiblewalled tank 20 stores water under predetermined pressure for immediateavailability at the outlets when needed. A switch 22 sensitive to linepressure energizes or deenergizes the motor as required to maintainsystem pressure substantially constant. However the problem with such asystem is that frequent recycling of the pump motor occurs when water isnot being used to nearly the full capacity of the pump, such as whenonly one or a few of the several outlet valves is opened, because offirst (a) the rapid buildup of line pressure, causing the switch to shutoff the pump motor, followed by (b) the rapid dissipation of linepressure which again causes the switch to reactivate the motor. Suchconstant recycling is very hard on motor and pump parts, causing partswhich should Wear for years to wear out Within relatively short periodsof time.

The problem of rapid pump recycling is particularly serious inconventional prior art systems as shown in FIG. 1 where there is a greatdistance between the water tank 20 and pressure switch 22, such as infarm systems where distances of one thousand feet or more often separatethe well and pump house from the tank. In such instances, when the pumpshuts off, water moves back and forth in the discharge line betweenpressure switch 22 and the tank for a period of time. This movementcauses alternate increases and decreases in pressure against pressureswitch 22 in rapid succession, which in turn starts 3,493,001 PatentedFeb. 3, 1970 and stops pump motor 12 at frequent intervals until lintfriction finally stops the water movement.

SUMMARY OF THE INVENTION The present invention overcomes the recyclingproblem of prior demand pressure pumping systems througf a novelcombination of features which includes (1) providing a switch for thepump motor which is sensitive tc tank pressure rather than linepressure, (2) connecting the pressure tank in parallel with the outlets,(3) providing a check valve between the main delivery pipe and the inletto the pressure tank which prevents filling oi the tank but permitsunrestricted discharge of fluid from the tank, and (4) providing abypass orifice which bypasses the check valve to permit a slow,controlled filling of the pressure tank and thus only a slow buildup oftank pressure to the motor shutoff point when the pump is operating.

Accordingly, primary objects of the invention are to provide:

(1) A hydraulic pressure demand pumping system which eliminates theproblem of constant recycling of the pump motor;

(2) A pumping system as aforesaid which utilizes for the most partconventional elements of prior systems;

(3) A pumping system as aforesaid which is simple and economical toinstall, operate and maintain;

(4) A system as aforesaid which requires a minimum capacity pressurestorage tank;

(5) A system as aforesaid which isolates surges of water pressureresulting from water hammer after the pump shuts off from the pressureswitch and thus prevents rapid starting and stopping of the pump motorfollowing initial stopping of such motor;

(6) A bleeder-check valve for use With a system as aforesaid; and

(7) A method of converting existing hydraulic pumping systems to reducethe frequency of pump recycling.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other objects andadvantages of the invention will become more apparent from the followingdetailed description which proceeds with reference to the accompanyingdrawing wherein:

FIG. 1 is a schematic view of a common prior art pumping system;

FIG. 2 is a schematic view of a pumping system in accordance with thepresent invention;

FIG. 2A is a schematic sectional view of the check valve unit of thesystem of FIG. 2, on an enlarged scale;

FIG. 3 is a schematic view of a modified pumping system in accordancewith the present invention; and

FIGS. 4 and 5 are enlarged views, partly in section of bleeder-checkvalves suitable for use in the system of the invention.

DETAILED DESCRIPTION With reference to the drawing, FIG. 2 illustrates apumping system of the invention including a pump 30 driven by a constantspeed electric motor 32 to deliver water or other fluid from a well orsump 34 through suction line 36 into a delivery pipe 38. Main pipe orconduit 38 leads to branch supply pipes 40, 41 of, for example, ahousehold water system having a plurality of outlets 43a, 43b, 43c and43d provided with individual shutoff valves 45a, 45b, 45c, 45d,respectively.

Pressure accumulator means comprising tank 48 having flexible,expansible walls 49 housed within a metal shell 50 is connected to maindelivery pipe 38 in parallel with outlets 43 by a short length of pipe52. A pressure switch 54 on the tank is sensitive to pressure Within thetank and .ectrically connected to motor 32 by conductor 56 to antrol thesupply of electrical current to the motor. The ressure switch activatesthe motor when tank pressure rops below a predetermined minimum anddeenergizes 1e motor when pressure rises to a predetermined laximum.

A one-way or check valve means 58 in pipe 52 beveen main supply pipe 38and the accumulator tank preents inflow of fluid into the tank from thesupply line 'hile permitting unrestricted flow of fluid from the tankhen an outlet valve is opened. However, a bypass orifice leans 60bypasses the check valve to permit the tank to ll slowly with fluid whenpump 30 is operating. FIG. A shows check valve 58 enlarged and somewhatless :hematically than FIG. 2 and with bypass orifice 60 xtendingthrough valve seat 62 of the valve unit. A valve all 64 prevents flowinto the tank through main valve pening 66 but does not close offorifice 60.

The system of FIG. 2 may also be provided with a ressure reducing valve68 in main supply line 38 in hose instances where the pump dischargepressure is onsiderably higher than the desire outlet pressure.

OPERATION In operation, when only one or several of the outlet alves areopened, there is an immediate supply of fluid t the outlets at thedesired pressure because of the rapid ischarge of available fluid frompressure tank 48. Subequently, when pressure within the tank drops belowthe lredetermined minimum setting of pressure switch 54, witch 54 closesto start pump motor 32 so that water at he desired pressure willcontinue to be supplied to the vutlets following the unloading of thepressure tank. vIotor 32 continues to operate until pressure within the.ccumulator tank 48 builds up to the predetermined maxi- Jurn shutoffsetting of the pressure switch. Even if only vne or a few outlet valvesare opened, motor 32 will p rate for a considerable length of timebecause orifice 60 sized to prevent a rapid buildup of fluid pressurewithin he tank following its initial discharge. Ideally, orifice 60hould be sized so that the tank will not reach shutoff IICSSHIG evenwith only one outlet valve open until such 'alve is reclosed, wherebythe motor runs continuously luring the drawing of any appreciablequantity of water rom the system.

EXAMPLE Assuming a desired outlet pressure of 50 p.s.i., the ump orpressure reducing valve would be selected acordingly. A suitablepressure accumulator tank might be Jacuzzi Hydrocel brand tank of threeor five gallon apacity capable of withstanding 75 p.s.i. hydraulicpresure. Under these circumstances the pressure regulator vould be setto shut off the pump motor when the presure within the tank reaches 40to 65 p.s.i. The minimum ize of orifice under these conditions should beapproximately one-sixteenth of an inch. It has been found that lnderthese conditions and using a pump with a discharge ressure of 55 p.s.i.with only one or a few outlet valves pen, water will enter the pressurestorage device at a ate of about eight-tenths of a gallon per minute.

FIG. 3 EMBODIMENT FIG. 3 illustrates the conversion of a conventionalin- .talled water system having the usual rigid-walled presure tank 70to a system in accordance with the present nvention. The tank has an airspace 72 exerting pressure m the surface 74 of water within the tank toplace the .ystem under pressure. The conversion is accomplished vycapping the normal outlet 76 of the tank, bypassing he tank with themain delivery pipe '78, and moving the iressure-sensitive control switch80 from the main deivery pipe as shown in FIG. 1 to the tank as shown inFIG. 3 so that it acts in response to tank pressure rather han linepressure. Then a bleed-check valve 82 with bypass orifice 84 isinstalled in the inlet pipe 86 to the tank so that the tank will unloadrapidly but fill slowly. Thus the pressure tank will be connected inparallel with outlets 88, and the system will operate in the same manneras previously described with reference to the system of FIG. 2.

FIGS. 4 and 5 illustrate practical embodiments of bleed-check valvessuitable for the above-described systems of FIGS. 2 and 3. In theembodiment of FIG. 4 bypass bleed orifice 90 passes through valve disc92, which seats against valve seat 94 to prevent all but a minimal flowinto the tank. The tubular valve body 96 may be threaded at its oppositeends (not shown) to provide for ready coupling to the accumulator tankand other pipe elements.

In the valve of FIG. 5, the bypass bleed orifice 98 passes through anannular valve seat 99. A ball closure 10%) of the valve is made ofrubber or other nonmetallic material to prevent excessive noise in thesystem upon closure of the valve.

In addition to being an important element in preventing rapid recycling,the bypass bleed orifice in the check valve means of the system isolatesthe accumulator tank and pressure switch from the effects of water surgeand water hammer in systems particularly subject to such conditions.

Having illustrated two embodiments of my invention, it should beapparent to those skilled in the art that the same permits ofmodification in arrangement and detail.

Iclaim:

1. In a hydraulic pumping system:

pump means,

conduit means extending downstream from a discharge side of said pumpmeans to an outlet, shutoff valve means at said outlet, hydraulicpressure accumulator means connected in said conduit means in parallelwith said outlet,

valve means in said conduit means between said pump means and saidaccumlator means and in parallel with said outlet,

said valve means including means permitting rapid fiow from saidaccumulator means and slow flow into said accumulator means to providean immediate supply of fluid at predetermined pressure at said outletwhen said shutoff valve means is opened and to provide a slow buildup ofpressure in said accumulator means while said shutoff valve remains openand during the operation of said pump means,

and pressure-sensitive pump-operating means responsive to predeterminedpressures in said accumulator means for activating and deactivating saidpump means. 2. A system according to claim 1 wherein said pump meanscomprises a pump driven by a constant speed motor and including pressuresensitive means responsive to a predetermined low pressure in saidaccumulator means for activating said motor and responsive to apredetermined high pressure in said accumulator means for deactivatingsaid motor.

3. A system according to claim 1 wherein said outlet means comprises aplurality of outlets, said shutoff valve means includes a separateshutoff valve for each outlet and said valve means includes orificemeans sized to provide a slow buildup of fluid pressure within saidaccumulator means when only one of said shutoff valves is open.

4. A system according to claim 1 wherein said valve means includesbypass orifice means integrated within a common valve body.

5. A system according to claim 1 wherein said accumulator meanscomprises a closed tank having walls of flexible expansible material.

6. A system according to claim 1 wherein said accumulator meanscomprises a closed tank having rigid walls and an air space within anupper portion of said tank.

7. A system according to claim 1 including high pressure regulatingmeans in said conduit means between said pump means and said valve meansfor controlling the maximum pressure at said shutoff valve means andsaid accumulator means.

8. In a hydraulic pressure demand pumping system including amotor-driven pump for delivering fluid to a valve controlled outletmeans in a delivery pipe, and a pressure accumulator tank having aninlet connected to said pipe, a valve means for controlling the inflowand outflow of fluid from said tank comprising:

said valve means including valve closure means preventing the flow offluid into said tank and permitting the unrestricted outflow of fluidfrom said tank,

bypass orifice means bypassing said closure means so as to permit acontrolled, restricted flow of fluid into said tank at a ratesubstantially less than the rate of said outflow from said tank,

and pressure sensitive switch means sensitive to pressure in said tankfor activating and deactivating said pump.

9. A valve means according to claim 8 wherein said closure meansincludes a stationary valve seat defining a valve opening and a movablevalve closure element engageable with said seat for closing saidopening, said orifice means passing through said closure element.

10. A valve means according to claim 8 wherein said closure meansincludes a stationary valve seat defining a valve opening and a movablevalve closure element engageable with said seat for closing saidopening, said orifice means passing through said seat.

11. A valve means according to claim 10 wherein said closure element iscomposed of a rubber or other nonmetallic material.

12. A method of preventing rapid recycling of a pump motor in a demandpressure hydraulic pumping system including a motor-driven pump whichdelivers water from a source to one or more outlets through a closedconduit,

said pump having a flow capacity greater than that of one of saidoutlets,

said method comprising the steps:

accumulating a supply of hydraulic fluid at approximately systempressure adjacent to said conduit,

upon the opening of one of said outlets, discharging fluid rapidly fromsaid supply into said conduit to provide fluid immediately at said oneoutlet at system pressure,

sensing the pressure of said supply and activating the pump motor tooperate said pump when the pressure of said supply reaches apredetermined minimum to pump fluid from said source to said outlet,

slowly rebuilding said supply by diverting a small restricted portion ofthe flow from said pump and conduit to said supply while continuing tosense the pressure of said supply,

and continuing the operation of the pump until the pressure of thesupply reaches a predetermined maximum, then deactivating the motor tostop the operation of said pump.

References Cited UNITED STATES PATENTS ROBERT G. NILSON, PrimaryExaminer U.S. Cl. X.R.

